Remote control system



Nov. 10, 1936. A MOF'FETT 2,060,772

REMOTE CONTROL SYSTEM Filed May 10, 1934 JYQ T Inventor: (5 5 A. Mofett,

His Attornqg.

Patented Nov. 10, 1936 PATENT OFFICE REMOTE CONTROL SYSTEM Guy A.Moifett, Rexford, N. Y., assignor to General Electric Company, acorporation of New York Application May 10, 1934, Serial No. 724,845

13 Claims.

My invention relates to remote control systems. v

It is an object of ;my invention to provide a system in which acharacteristic of the source of supply may be altered by means of acontrol circuit completed through a load circuit connected to saidsource of supply. It is a further object of my invention to provide asystem in which a plurarity of relays, one or more of which are arrangedto be energized through a load circuit, are employed for raising orlowering the voltage of a generator to which said load circuit isconnected under the control of means arranged to be connected in saidload circuit for limiting the flow of current to values below thosenormally supplied but sufficient to operate one or more of said relays.

Further objects of my invention will becom apparent from the followingdescription taken in connection with the accompanying drawing, Fig. .lof which diagrammatically represents a system embodying my invention,and Fig. 2 of which shows an indicator and controller for use in asystem such as shown in Fig. 1.

The system shown in Fig. l of the drawing comprises a generator l0 whichis connected to a load device through a load circuit ll, l2. Thegenerator is driven by amotor l3 mechanically connected thereto. Thismotor is illustrated as an electric motor which is connected to a sourceof supply M.

The particular system illustrated is an arc weldingsystem in which theload device comprises the are established between an electrode I5 andthe work IS. The work is connected to generator l0 through loadconductor l2 and the electrode is arranged to be held inia welding toolor holder H by means of which current is supplied thereto through loadconductor II. The

,electrode holder is also provided with a plurality of terminals l8 andI9 through which a circuit including conductors II and I2 may becompleted. The impedance of the terminalconnections 8 and I9 aredifierent and greater than the impedance of the connection through theelectrode l5 and the clamp in which this electrode is supported.

The completion of a circuit through terminals l8 or is is used tocontrol the voltage of generator l0 through the agency of relays 20 and2|. The completion 'of a circuit through electrode l5 closes switch 22whose operating coil 23 is connected in shunt thereto and whose hold ingcoil 24 is connected in series therewith. By

" reason of the connections illustrated in the drawing switch 22 isclosed by the combined effect of the flow of current through both coils23 and 24. Since, however, the principal efiect is due to coil 23, thiscoil is designated as the operating 0011. It is, of course, apparentthat a circuit through coil 23 can be completed independently of thecoil 24 in which case coil 23 would be the sole operating winding.Relays 20 and 2| are connected in series with one another and with theoperating coil 23 of the switch 22. These relays are arranged to operateon difierent current values both of which are less than the currentvalue at which switch 22 operates.

The closure of switch 22 completes through contacts 25 a short circuitabout the operating windings of relays 2D and 2| thus preventing anytransformer action between its coils 23 and 24 circulating currentthrough these windings. If necessary resistance 26 may be connectedacross the operating coil of the relay 20 to delay its operation so thatit will close subsequently to the closure of the switch 22.

The generator I0 is of the type described and claimed in U. S. LettersPatent No. 1,340,004, Sven R. Bergman, granted May 11, 1920. In thistype'oi' generator the electromctive force between a main brush 2! andan auxiliary brush 2B is substantially constant, while the electromctiveforce between the auxiliary brush 28 and a main brush 29 changes invalue and direction in accordance with'the condition of the arc. Thegenerator is illustrated as having a field 30 connected through arheostat 3| to the substantially constant potential between brushes 21and 28 and a series field 32 provided with taps which are connected tosegments 33 of a switch 34 the position of the arm 35 of whichdetermines the number of series field turns connected in the loadcircuit l2. The rheostat 3| and tap switch 34 are mechanically connectedto and driven by a pilot motor 36 which is rotated in one direction oranother depending upon the closure of one or both of. relays 20 and 2|.The tap switch 34 is operated through a Geneva movement 31 to change thenumber of turns of the field 32 connected in the load circuit at thetime the rheostat 3| changes from a. maximum to a minimum or a minimumto a maximum position due to the rotation imparted thereto by the pilotmotor '35. By thus controlling the fields of the generator) a wide rangeof adjustment is provided. I

Theconstruction of the system will be further described in connectionwith its operation.

Inthe drawing the various parts have been illustrated in the positionsthey assume when deenergized.

If the welding operator desires to raise or lower the voltage of thegenerator l0 he can accomplish this result by completing a circuitthrough either terminal II or terminal ii. The circuit through terminalI! is of greater impedance than the circuit through terminal i9, andboth of these circuits are'ot greater impedance than the circuit throughelectrode l5 and the clamp in which this electrode is supported inholder II. By touching terminal I! to the work It a circuit is completedthrough the load circuit ll, l2, the operating windings of relays 20 and2| and the wind ings 23 and 24 0! switch 22. Due to the impedance ofthis circuit the current flow is limited to a value sufllcient only tooperate relay 20. The closure of relay 2' completes through its contacts28 a control circuit for the motor 26 by means of which this motor isoperated in a direction to increase the voltage of the generator it.This circuit is as follows:--From main brush 21 0! the generator llthrough conductor ll, contacts I! o! relay 20, contact 22 of relay 2|,conductor 40. limit switch ll, conductor 42, motor 22, and conductor 42to the auxiliary brush 22 of the motor ll. In the arrangementillustrated the limit switch been connected in the load circuit, and theoperation or the relay 2. will consequently produce no :l'urtherincrease in the voltage of the generator. 1!, however, the operatorcompletes a circuit through the terminal II a circuit oi lower im-'pedance will be established and a greater how of current will occurrelays 20 and 2|. The operation of both of these relays will complete acontrol circuit for the motor 2' by means of which the voltages! thegenerator II will be decreased. This circuit is as !ollows:-Frommain-brush 2| or generator ll through conductor ll, contacts 22 of relay2!, contacts 44 or relay 2|, conductor 5,. limit switch I, conductor 41,motor 2t and conductor 42 to the auxiliary brush 22 oigenerator ll.

When a circuit is completed through terminals II and it its impedance isso great that enough current will not flow to energize the coils 22 and24 otthe switch 22 suillciently to close it. If,however, the weldingcircuit is completed by touching the electrode I! to the work II, acircuit of much lower impedance is completed and the switch 22 will besufllciently energized to close the closure of switch 22 completes itsholding circuit through its coil 24 connected in series closure ofswitch 22 also completes through contacts 25 a short circuit about theoperating coils of the relays 22 and 2|. During welding the fluctuatingcurrent through coil 2i oi switch 22 may introduce in the winding 22 o!the switch 22 through transformer action a current snflicient to operatethe relays 22 and 2| and by. short circuiting these coils throughcontacts 2' such operation is prevented.

In'order to prevent momentary energisation of it is essential that theswitch 22 -minal iii and the ground connection ll is in an open positiondue to the fact that all of the series held 22 has i which will energizeboth therewith. The

when the welding operator strikes 'asiallwithinthe istic which willprevent repeated operation of this switch when the operator repeatedlystrikes an arc during welding.

The terminals II and I9 may be eliminated from the electrode holder l1by providing a controller box I diagrammatically illustrated in Fig. 2.This controller box is provided with two circuits or diflerentimpedance, each 0! which is sufllciently great to prevent the operation0! the switch 22 when connected in circuit therewith. The circuit ofgreater impedance is connected between an electrode terminal 50 andaground connection It, and the circuit of lesser impedance is connectedbetween the electrode ter- 49. The arrangement is such that when theelectrode II is touched to the terminal 50 when the ground connection 49is in engagement with the work It, an operating circuit is completed forrelay 22, and when the electrode is touched to the terminal 5| under thesame conditions an operating circuit is completed for relays 20 and 2|.Thus, by touching the electrode II to the terminal ll the voltage of thegenerator I! can be raised, and by touching the electrode I! to theterminal 5| the voltage of the generator can be lowered. An electricalinstrument illustrated as connected between the terminals 50 and box 42may be used to indicate the change in either or both generator voltageand current accomplished by completing the welding circuit through thecontrol box for a predetermined length 0! time.

The possibility of burning and I! of theelectrode holder 50 and SI ofcontrol box energy to be dissipated in either of the circuits completedthrough these terminals will not in most cases exceed watts.

It is apparent that the systems illustrated may be variously modifiedwithout spirit and scope 0! my invention. For example, voltageresponsive relays may be used in place of the current responsive rilays22 and 2|. Furthermore, other arrangements may be employed forcompleting circuits oidiilerent and greater impedance than the normalimpedance of the welding circuit. It is also apparent that the controlsystem described may be used ior altercharacterlstic o! asource ofsupply and is not limited to a voltage control system such asillustrated. ,It is also apparent that any type of welding generatormaybe employed. and any suitable arrangement may be used for controllingthe field energization of its generator in response to the operation 0!the relays run-responding to the relays 22 and 2| oi the particularembodithe terminals II II, or the terminals 0 is negligible as the mentillustrated and described above) These-lid States, is:-

departing from the u I of the control aiimhmodiilcauonstrueapiritandscopeoimy LAriowersystem'comprisingamrceotmp-u operation ofsaid relays.

ply, a load circuit connected to said source of supply, a plurality ofrelays one or more of which are arranged to be energized through saidload circuit in accordance with its impedance, means for altering orreversely altering a characteristic of said source of supply dependingon the operation of one or more of said relays, and means arranged to beconnected in said load circuit to control its impedance and theoperation of said relays.

2. A power system comprising a source of supply, a load circuitconnected to said source of supply, means arranged to be energizedthrough said load circuit in accordance with its impedance for alteringa characteristic of said source of supply, and means arranged to 'beconnected in said load circuit for controlling its impedance andforindicating the alteration in said characteristic of said source.

3. A power system comprising a source of supply, a load circuitconnected to said source of supply, means arranged to be energizedthrough said load circuit in accordance with its impedance for alteringa characteristic of said source of supply, means arranged to beconnected in said load circuit for controlling its impedance, and meansassociated with said last mentioned means for indicating an alterationin said characteristic.

4. A power system comprising a source of supply, a load circuitconnected to said source of supply, a plurality of relays one or more ofwhich are arranged to be energized through said load circuit inaccordance with its impedance, means for altering or reversely alteringa characteristic of said source of supply depending on the operation ofone or more of said relays, means arranged to be connected in said loadcircuit to control its impedance and the operation of said relays, andmeans associated with said last mentioned means for indicating thecondition of said generator with regard to said characteristic.

5. A power system comprising a generator, a load circuit connected tosaid generator, a switch in said load circuit arranged to be closed whensaid load circuit is completed under normal operating conditions, acontrol circuit in shunt to said switch, a plurality of relays in saidcontrol circuit one or more of which are arranged to operate inaccordance with the impedance of said load circuit, means including saidrelays for raising or lowering the voltage of said generator dependingon the operation of one or more of said relays, and means for increasingthe impedance of said load circuit above normal to values determiningthe operation of one or more of said relays.

6. A power system comprising a generator, a load circuit connected tosaid generator, a switch in said load circuit arranged to be closed whensaid load circuit is completed under normal operating conditions, acontrol circuit in shunt to said switch, a plurality of relays in saidcontrol circuit one or more of which are arranged to opcrate inaccordance with the impedance of said load circuit, means including saidrelays for raising orlowering the voltage of said generator depending onthe operation of one or more of said relays, andmeans arranged to beconnected in said load circuit to control its impedance and the 7. Apower system comprising a generator, a load circuit connected to saidgenerator, a switch in said load circuit having an operating coilconnected in shunt thereto and a holding coil connected in seriestherewith, two relays-having operating coils connected in series withone another and with the operating coil of said switch and arranged tooperate at different current values both of which are less than thecurrent value at which said switch operates, means for raising orlowering the voltage of said generator depending on the closure of oneor both of said relays, and means for limiting the flow of ourrent insaid load circuit to values operating one or both of said relays butinsuflicient to operate said switch.

8. A power system comprising a generator, a load circuit connected tosaid generator, a switch in said load circuit having an operating coilconnected in shunt thereto and a holding coil connected in seriestherewith, two relays having operating coils connected in series withone another and with the operating coil of said switch and arranged tooperate at different current values both of which are less than thecurrent value at which said switch operates, means for raising orlowering the voltage of said generator depending on the closure of oneorboth oi. said relays, means for limiting the flow of current in saidload circuit to values operating one or both of said relays butinsufficient to operate said switch, and a closed circuit about theoperating coil of said switch arranged to be completed upon the closureof said switch.

9. A power system comprising a generator, a

load circuit connected to said generator, a switch in said load circuithaving an operating coil connected in shunt thereto and a holding coilconnected in series therewith, two relays having operating coilsconnected in series with one another and with the operating coil of saidswitch and in I shunt to said switch, said relays being arranged tooperate at difiei'ent current values both of which are less than thecurrent value at which said switch operates, means for raising orlowering the voltage of said generator depending on the'closure of oneor both of said relays, means for limiting the flow of current in saidload circuit to values operating one or both of said relays butinsufflcient to operate said switch, and a short circuit about theoperating coils of said relays arranged to be completed upon the closureof said switch.

10. A power system comprising a generator, a load circuit connected tosaid generator, a switch in said load circuit having an operating coilconnected in shunt thereto, a relay having an operating coil connectedin series with the operating coil of said switch and in shunt to saidswitch, said relay being arranged to operate at a lesser current valuethanthe current value at which said switch operates, means for alteringa characteristic of said generator depending on the closure of saidrelay, means for limiting the flow of current in said load circuit to avalue sufllcient to operate said relay but insufllcient to operate saidswitch,

and a short circuit about the operating coil of said relay arranged tobe completed upon the closure of said switch, said switch being adaptedto close more rapidly than said relay when both said switch and saidrelay are simultaneously sufficiently energized to operate them to theirclosed positions.

11. A power system comprising a source. of

supply, a load circuit connected to said source of supply, meansarranged to be energized through said load circuit in accordance withits impedance for altering a'characterfitic of saidsource of supply, andmeans arranged to be connected in said load circuit for controlling itsimpedance and the operation of said last mentioned means.

12. A power system comprising a generator, a load circuit co'nnected tosaid generator, a switch in said load circuit arranged to be closed whensaid load circuit is completed under normal operating conditions, arelay having its operating coil connected in shunt to said switch, meansfor altering a characteristic of said generator depending on the closureof said relay, means for limiting the flow of current in said loadcircuit to a value sufllcient to operate said relay but insuflicient tooperate said switch, and a short circuit about the operating coil ofsaid 'relay arranged to be completed upon the closure of said switch,said switch being adapted to close more rapidly than said relay whenboth said switch and said relay are simultaneously sufllcientlyenergized to operate them to their closed positions.

13. A power system comprising a generator, a load circuit connected tosaid generator, a switch in said load circuit having an operating coilconnected in shunt thereto and a holding coil connected in seriestherewith, a relay having an operating coil connected in shunt to saidswitch and in series with the operating coil of said switch upon theclosure of said switch, means for altering a characteristic of saidgenerator depending on the closure oi said relay, means for limiting theflow of current insaid load circuit to a value sumcient to operate saidrelay but insufficient to opcrate said switch, and a short circuit aboutthe operating coil oi! said relay arranged to be completed upon theclosure of said switch.

GUY A. MOFFEI'I'.

CERTIFICATE OF CORRECTION.

Patent No. 2,060,772.

for "close the" read close.

November 10, 1936.

our A. MOFFETT.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: column,line 45, for the words "contacts 44 or" read contact 44 of; line 53 The;and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this 26th day of January, A. D. 193'? (Seal) Page 2,first Henry Van 'Arsdale Acting Commissioner of Patents.

